1. Field of the Invention
The present invention relates to a flexible endoscope in which an optical fiber of a light transmission module provided at a rigid distal end portion is inserted through an insertion section.
2. Description of the Related Art
An endoscope includes an image pickup device such as a CCD at a rigid distal end portion of an elongated flexible insertion section. In recent years, use of an image pickup device having a large number of pixels in an endoscope has been examined. When the image pickup device having the large number of pixels is used, a signal amount transmitted from the image pickup device to a signal processing apparatus (a processor) increases. Therefore, optical signal transmission via a thin optical fiber by an optical signal is desirably performed instead of electric signal transmission via a metal wire by an electric signal. For the optical signal transmission, an E/O module (an electro-optical converter) that converts an electric signal into an optical signal and an O/E module (a photoelectric converter) that converts the optical signal into an electric signal are used.
For example, Japanese Patent Application Laid-Open Publication No. 2013-025092 discloses a light transmission module including an optical element that performs input or output of an optical signal, a substrate mounted with the optical element, a holding section including a through-hole for optical fiber insertion for transmitting the optical signal inputted to and outputted from the optical element and disposed along a thickness direction of the optical element.